Linear and switch-mode voltage regulators constitute fundamental building blocks of today's power management integrated circuits (ICs). One such type of regulator is known as a switching regulator or switching power supply, which controls the flow of power to a load by controlling the on and off duty-cycle of one or more power switches coupled to the load. As an example, a switching regulator can reside in an IC, such that external feedback resistors and an external inductive power source are coupled to the switching regulator to provide a regulated voltage potential at the output of the inductor.
A typical switching converter implements pulse-width modulation (PWM) for controlling the duty-cycle of the one or more power switches coupled to the load. As an example, an error amplifier provides a signal corresponding to a difference between a reference voltage and a feedback voltage to a comparator that outputs an AC switching signal that defines the duty-cycle for the activation and deactivation to the one or more power switches. To protect the power supply system from current overload conditions, the current through the one or more power switches can be limited. As an example, current can be limited through the one or more power switches by a voltage clamp that limits the maximum output voltage of the error amplifier. However, for a power regulator that employs slope compensation to mitigate sub-harmonic instability of the duty-cycle, the current limit for the one or more power switches is typically dependent on the duty-cycle of the switching signal. As an example, in a typical boost regulator, the current limit through the one or more power switches can decrease as the duty-cycle increases. Accordingly, there is little control that can be exhibited over the maximum amount of current provided over a variety of ranges of desired input and output voltages.